Solvent deasphalting is a current process for demetallation of petroleum residuum. The metals concentrate in the solvent-insoluble phase and the deasphalted oil is decreased in metals content. A limitation of art-processes is that as the yield of deasphalted oil increases, so does the metals content. There is a continuing need for refinement of the solvent deasphalting process which produces a high yield of deasphalted oil with a low metals content.
Solvent deasphalting (i.e., extraction of asphaltenes from petroleum stocks is typically accompanied with removal of organometallic, e.g., organo-nickel and vanadium and heteroatoms) is a key aspect of resid upgrading. Solvent deasphalting to produce the foregoing deasphalted oils (DAO) typically is accomplished using suitable hydrocarbonaceous solvents, in particular, hydrocarbons of straight chain paraffins and isoparaffins, containing from 3 to 7 carbon atoms. Most widely known processes are those known as Propane Deasphalting (PDA), Solvent Deasphalting (SDA) and Residual Oil Solvent Deasphalting (ROSE). Solvent deasphalting in this manner is well known in the art, see e.g., U.S. Pat. Nos. 3,975,396; 5,008,838; 5,466,365 and 4,125,458. Applicants' process addresses the "high yield/high metals" limitation of the art.